Mechanisms of the Heart
by Lucenthia
Summary: After the war with the giants, Nico accidentally shadow travels into Bunker 9, where Leo's outfitting the Argo II to look for Calypso. Nico finds more in common with Leo than he thought possible, and after a while, he feels more for Leo than he thought possible. And all throughout, Leo is unaware of Nico's feelings as he looks for Calypso.


**Well, this started out as an attempt to do something more light hearted than my last oneshot, and I think it's not especially tragic. It's pretty long, but I hope you enjoy it!**

* * *

Nico really didn't like machines or anything remotely resembling something that was supposed to work. The first subtle sign Leo had gotten was when he saw Nico breaking the door off Bunker 9 and try to put it back on upside down.

Leo wasn't that annoyed at the door breaking. He'd been meaning to replace it for a while, ever since he had started outfitting the _Argo II_ and decided to put in a turbo engine in case the magical oars and sails somehow malfunctioned.

What did annoy him was the fact that Nico broke the door while shadow travelling with Mrs. O' Leary.

"Not cool, man!" Leo yelled over the sound of the blowtorch he was handling. "I don't like hellhounds in this bunker. Make sure she doesn't touch- Ah, sweet Hephaestus."

Leo put down the blowtorch without melting the wood of _Argo II _and ran over to extract Mrs. O' Leary from a net that had sprung out of a sphere she had thought was a doggy treat. "Bad hellhound," Leo said slowly, bending down a little so he could look Mrs. O' Leary in the eye, "Don't eat a replica of Archimedes' statute. Bad hellhound."

Once he was convinced Mrs. O' Leary looked suitably repentant, he looked around to see Nico trying to lift the door and put it back in its frame.

"Hey, Nico." Leo took off the visor he'd been wearing as he had been welding two frames together to support the new turbo engine that he'd get around to installing. "The side with the lock is supposed to go on the side of the frame without hinges." He quickly ran over and guided the door over to a space in the floor that was cleared of devices, tools, weapons, and any other bits that usually wound up somewhere in Bunker 9.

Nico looked at the open frame that acted as a huge window to the forest, where he could see Dryads and Satyrs running around aimlessly. He paused for a moment, then said, "Sorry."

"Hey, it's cool." Leo said as he dusted off his hands and headed back to his latest project, "Just keep Mrs. O' Leary away from stuff like… that solar powered screwdriver she just put in her mouth." Leo finished the sentence with a groan.

Nico whistled and said, "Here, girl!" Leo thanked himself for making sure the screwdriver had been extra-waterproof as he looked at the slobber that now coveredit. Then he cringed as Nico's hellhound knocked two tables to the side as she bounded over to where Nico was, almost flattening Leo in the process.

"Don't mind me," he muttered, "Just some random demigod here for you to eat up."

"She doesn't eat children of Hephaestus." Nico replied, "She says their skin's too tough."

Leo frowned up at Nico, not knowing whether he was joking or not. Then Nico raised an eyebrow and his lips twitched. Leo rolled his eyes and said, "Very funny. Make fun of the ugly dwarf, why don't you guys?"

Nico shrugged, and Leo went on to ask, "So why are you here? Why did you have to come busting in?"

"There's this big gathering up at Camp and I wanted to avoid it. I just came here by accident." Nico rested his head on Mrs. O' Leary's belly and stared up blankly at Leo. "Why aren't you there?"

In fact, now that Nico said it, Leo remembered Jason and Piper telling him yesterday. But he had forgotten, like always. Building a ship to Ogygia was more important. "I've got better things to do." Leo said, "I've got stuff to do."

"Does it involve installing a canon onto the top of _Argo II?_" Nico asked. He was looking at a small structure that was hanging from the ceiling.

"Nah, that's a super spotlight that I've designed." Leo said, "It can light up anything within a kilometer once I've got it working again."

"What about that ball over there?" Nico dismissed Mrs. O' Leary and Leo let out a sigh of relief when he saw the hellhound disappear. "Dude, that "ball" is Archimedes' Sphere. That's like calling Poseidon's Trident "that pitchfork"."

Nico walked over to the sphere and picked it up gingerly. "It looks cool."

"I am doomed to be an unappreciated genius." Leo sighed tragically, "You are holding something children of Athena, Hephaestus, Ares, and pretty much anyone interested in war and inventions would kill for, and you say 'it looks cool.'"

To prove his point, Leo walked up to the sphere and slotted it into an indent in the wall. Nico's eyes widened when images were projected onto the ceiling like constellations. "Is that a table like Buford?" Nico squinted to try and read the ancient blueprints.

"No, that's the solar laser that could blow up ships."

"And what about the design for the city over there?"

"Dude, that's the earliest record of pipes and aquaducts in Greek history!" Leo said outraged.

Nico smirked before letting his face fall back into the deadpan mask everyone was used to. "I should be going now. Mrs. O' Leary will be wondering where I am, and I promised to feed her a couple of Ares' kids."

"Ew, why would she want to eat one of them?" Leo scrunched up his face. "They've probably all got lice and bugs on them."

Nico shrugged as he started to shadow travel. "He likes the muscle. Thighs are his favorite part."

Leo laughed and said, "Hey, Nico. If you ever want to drop by, well, my door's always open."

Nico looked at the door guiltily before saying, "I'll fix it."

Then he left, and Leo was left there smiling for a minute before realizing that he had just had a conversation with one of the most notorious demigods in the camp. Chuckling to himself, Leo went back and started to work on his super turbo engine.

* * *

The second time Nico came in he got captured by Buford, the helicopter-decoy-table.

Leo had been hanging on the bottom of the _Argo II _when Nico had shadow travelled into the Bunker again and tripped over the table that could fly around carrying smelly underwear. As it was, Leo just considered Nico lucky that all Buford did was hang Nico upside down while flying around the lab.

Leo jumped down and was looking for Buford's remote when Nico shadow travelled again and landed on _Argo II. _"You need to get your inventions under control, Valdez."

Leo looked offended. "Maybe if we didn't have demigods shadow travelling into them, they wouldn't be out of control."

"Which is why," Nico grunted, "Buford stole the remote control so it couldn't ever be controlled again." He took out the remote Leo had been looking for and handed it to him. Leo opened his mouth, then closed it again and carefully navigated Buford over to a ledge near the roof of the Bunker where no demigod could accidentally entrap himself in an avalanche of stinky underwear and socks.

"Anyways," Leo asked, "Why are you here?"

"I was bored and you have some cool stuff in here." Nico said, grabbing a random object from one of Leo's desks and fiddling with it. Leo was about to tell it was a bad idea when the miniature flamethrower Leo had been working on singed Nico's shoulder and ear. Maybe Nico was more ADHD than people gave him credit for.

"Okay." Leo said, as Nico glared at him, "First rule of being inside my bunker: don't touch anything unless I've told you what it does, okay?"

Nico nodded sheepishly. They stood there awkwardly for a few seconds before he cleared his throat and asked, "What were you doing before I got captured by Buford?"

"I was just fixing this spar in the bottom of the _Argo II._" Leo said, "I was just about to get this pulley system going so I can climb and hold stuff together and hold nails and tools at the same time."

Nico raised an eyebrow and said, "Or you could just find someone to pass stuff to you."

"Who's available?" Leo asked, "Jason and Piper are doing stuff, and so are Frank and Hazel and Percy and Annabeth." Nico's fist clenched quickly but Leo just wrote it off as an ADHD spasm. "All of the other Hephaestus kids are helping to rebuild the camp after Gaea's invasion. It'd be pretty selfish to get them to help me do this."

"Why are you overhauling the _Argo II_" Nico asked, "Are you going somewhere?"

"Yup!" Leo nodded and climbed on the hull of the _Argo II_. "Pass me that spanner."

Nico started to pick it up from the table when Leo yelled, "No! That's the electric wrench. And you were going to pick it up with the wrong end."

"So which one-"

"No, not that one. It's the third one from the right."

"Ow! Why the hell did that blow up?"

"Right, I meant the other right."

"Right or left? Make up your mind."

"No, I meant 'oh right' right, not the 'left-right' right."

"What?"

"Okay, lemme think, my right, your left."

"This one?"

"Right."

"You said left."

"Yeah, I meant left. I was saying 'I agree with you', right, not the-"

"For Hades' sake!"

Nico grumbled and thrust the spanner in Leo's face. "Why is it that everything you need is in the same place?" He bent down to retrieve the nails Leo had asked for, and this time he didn't accidentally get stabbed in the hand.

Leo mumbled his thanks as he started working on repairing the _Argo II. _"You should stick around me a little more if you're ever going to repair that door."

Nico looked over at the doorframe that was still wide open. "Right. I'll get onto that soon. You're not scared of stuff getting in and messing up the Bunker?"

"Nah, I don't care about that," Leo said, "You see, wait, pass me the hacksaw. No, that's the coping saw, I mean the- No, no, no, don't touch that. You'll get a finger sliced off. Yeah, that one." Leo reached down to pick up the hacksaw from Nico, whose eyes were shooting daggers at Leo's back. "You need labels."

"No, you just need to know what to touch and what not to touch." Leo retorted, "Anyways, no monster's going to come in. I set up super lasers and landmines all over the place. No monster's going to be coming in here."

"You've set up lasers and landmines around the bunker and you want me to stop shadow travelling in here." Nico gave Leo another flat stare that bounced off ineffectively.

"Don't worry," Leo grunted as he started yanking his hand back and forth as he clung to the bottom of the _Argo II _with his legs. "They know what humans look like. I'll even give you a key once you fix that door."

Nico smiled as Leo let go and dropped down on the ground. "There. All done. Wanna take a break?"

Nico nodded and said, "It's not like I've got anywhere else to be." He followed Leo to a corner of the bunker, taking care not to step on anything that looked like it might burn his foot off. It was even harder than the time he had jumped over the rivers of lava in the Fields of Punishment. For one thing, the floor was littered with metal things that moved. They spasmed left and right, and Nico felt like the devices were trying to trip him up.

By the time he had made his way to where Leo was, a scowl seemed glued to his face and sweat beaded his forehead. "You need to clean this place up."

"What are you, my mom?" Leo laughed. Nico frowned slightly but just shook his head. "You sure as hell need one."

Leo's reaction wasn't what Nico had expected. Leo just looked away and beckoned Nico over without even saying anything. Nico shook his confusion away and stepped forward. Leo beckoned even closer and said, "You need to step on the circle."

Nico looked down and saw a circle marked out with chalk a metre wide. "Why do we need to stand on that thing?"

Leo rolled his eyes. "Because I'm going to unleash an automaton that's going to kill everyone in the Bunker, and the circle protects us."

"Really?" Nico found the idea appealing, though he'd never admit that to anyone.

"No, Nico." Leo sighed and beckoned. "Come on, it's not going to be for long."

Giving Leo a distrustful look, Nico stepped forward into the circle, feeling uncomfortable as his elbow knocked into Leo's arm. Leo then pressed a button on the wall that Nico hadn't seen and they both shot up.

Nico would have fallen off if Leo hadn't been holding onto him. As it was, he had been prepared to shadow travel out of an uncomfortable collision with the floor. By the time Nico had gotten reoriented, the ride had stopped. The two of them were standing on top of the bunker, and Nico was grateful to see there weren't nearly as many gadgets and devices on the ground. In fact, there was only one.

Nico stepped forward, then realized he was still holding onto Leo's hand and let go. Rubbing it self-consciously against his black trousers, he stepped forward and looked at a huge mirror that was pointed to the sky. He looked down at the mirror and was instantly blinded by the glare of the reflected sun.

Leo laughed and said, "Didn't your mom tell you not to stare at the sun? Especially through a magnifying glass."

Nico glared back at Leo and said, "You could've warned me."

"I didn't know you'd stick your head directly into a revamped invention of Daedalus himself." Leo said, "You keep this up and I might just think you're as ADHD as Percy is."

Nico looked away and sighed. "I'm not like Percy." His eyes darkened before he asked, "Anyways, what does this do?"

"It uses sunlight and moonlight to see anything." Leo said, "But I'm trying to get it to see past magical enchantments as well. That and maybe have X-ray vision and GPS tracking."

"You do realize you have the power to spy on anyone and anything, don't you." Nico said, "And what's GPS, anyways?"

"Are the stories true?" Leo asked, "I never got a straight answer from Percy, but he said you were born in the 30's."

The two demigods looked at each other. Nico's eyes seemed to withdraw into his skull, and Leo remembered why even he'd been intimidated by Nico when they spent time together on the _Argo II. _He had tried talking to Nico back then, but it had only been a few days after Nico had been back from Tartarus, and there was still a tinge of insanity that lingered in his eyes.

There was another awkward silence and Leo went back to the shield mirror. "Anyways, I've been working on this for a while now, ever since we got back to camp. It seems to work decently for now, though I still haven't been able to find anything."

"Are you going on a treasure hunt or something?" Nico asked curiously, "You're outfitting the _Argo II, _you've invented a mirror that can see anywhere you want, and you've been unfocused ever since we got back, even for you."

"What makes you think I'm unfocused?" Leo asked indignantly, "I'm perfectly fine."

"You almost ran into two trees yesterday on your way to the dining hall." Nico replied. He looked at the mirror more cautiously now, running a finger over the lenses.

"You were there?" Leo asked, "I didn't see you."

"Exactly my point." Nico said, "So what are you looking for? It's got to be good if you're actually focusing on this for once."

Leo rolled his eyes. "My business, okay? I just wanted to show you this awesome creation. One day I'll be able to hook it up to the _Argo II _and see anything from my bedroom."

"You can't just show me this mirror and not talk about what you're doing with it." Nico stuffed his hands in his pockets as he realized he had talked more today than he had in a long time. Then he realized that was what he had just done to Leo. He had refused to tell Leo anything about his mom, and Leo had understood. He hadn't pressed for more information or bugged him like Nico was doing to him.

Maybe Leo had something just as important waiting for him at the end of his trail that involved mirrors, turbo engines and nails.

"I was born in the 30's." Nico said. He sat down on the roof of the Bunker and Leo lay down next to him, his legs tapping a complex rhythm on the hardened concrete of the bunker. "But dad put me in this place called the Lotus Hotel and Casino where time stands still. I spent two weeks in there, but seventy years passed outside."

"Why did your dad put you in that place?" Leo asked, "Did he just want you guys to live in the modern age or something with cool stuff like the PS4?"

"The pact between the Big Three." Nico said, "Zeus wanted me and," he took a deep breath before continued. "Bianca and I. But Hades didn't want to give us up, so he put us in the Lotus."

"What did you mom have to say about that?" Leo was twiddling a twig between his fingers and hadn't expected a chill to run down his spine. Nico wasn't looking at the forest in front of him anymore. He was staring into his memories. Leo knew the look. It had been what he had seen whenever he looked in the mirror weeks after his mother's death.

Then it hit him. The way Nico had hedged around the subject of the past and had clenched his fists when his mom was mentioned. Leo really needed to get working on that portable Slap Leo in the Face Machine, because he really needed it. "Look, man, if you don't want to-"

"Zeus killed her." Nico said quietly. He had summoned his Stygian Iron sword to his hand and was twirling it ominously. If Leo had met this guy for the first time, he would have run away as fast as he could. As it was, Leo stayed to listen, although he sat up and got ready to run.

"Zeus was trying to kill Bianca and I, but got my mom instead."

There was another pause in the conversation, and Leo wondered how he had gotten from showing Nico his super mirror that would have GPS tracking to talking about Nico's dead mom. "Is that why you acted weird around Jason?"

Nico's head snapped towards Leo's, and Leo backed up instinctively. "It's just that you avoided Jason half of the time during your stay on the _Argo II, _and I'm not so out of it that I don't notice you avoiding him now whenever you run into him."

Nico blushed and shook his head vigorously. "That's not it. And I _don't_ act weird in front of Jason."

Leo laughed before staring wistfully off into the distance. "You're a better man than I am, Nico. If Zeus had blasted my mom away, I would've hated him for a long time." Leo started tapping the Morse code that his own mom had taught him.

Nico sighed and stared at the ground, and stared even further down. "I did for a bit. But Percy taught me that we couldn't hate people forever. That sometimes hate and revenge wasn't a reason to live for."

Leo looked at Nico for a moment, then said, "I never hated Gaea for killing my mom, I hated myself."

Nico's eyes widened and he didn't say anything. He was good at that. Leo's fingers tapped on the cold concrete of the bunker faster. "It wasn't that hard seeing as the rest of my family did the same."

"You felt like you shouldn't exist, and that you were just doing it out of habit." Nico murmured, "You felt like nothing anyone did had a point, and you needed to shut yourself off from everything because everything was just going to hurt you."

Leo looked at Nico in surprise before slowly nodding. "I guess everything started changing once I met Jason and Piper. I'm not sure what, but-" Leo trailed off and stared sightlessly while Nico did the same.

There was another silence that lasted for several minutes. Neither of them said anything, they both just thought about what had once been and where they were now. Leo lay down on the roof of the bunker with his legs dangling off the edge and stared up at the clouds. Even Jason hadn't understood him that well. How could Nico of all people do it? Leo didn't even think Nico knew he existed on the _Argo II. _

Leo closed his eyes for a moment, then opened them several hours later. It was dark, and the moon was high in the air. He jerked up suddenly and saw that Nico had gone in the interim. Sighing, he dusted off his pants and started to go back down into Bunker 9. It occurred to him then that it was the first time he had slept for several hours in a long time. He had always snatched an hour or two here or there as he had worked on finding Calypso again.

As he walked through the bunker and thought about his mom again, he realized that he felt accepting of it. That he didn't feel that irrational guilt that always came whenever he thought of the moments he'd shared with her.

Leo smiled, then kept on working on the _Argo II._

* * *

Nico felt proud of himself as he shadow travelled into Bunker 9 without tripping over anything or injuring himself. He walked as directly as he could to Leo, who was wrestling with the wings of _Argo II. _He reached up and helped Leo hold the wing in place while Leo reached down and grabbed the electric screwdriver that Nico had almost picked up a few days ago. He fiddled with it for a few moments, then said, "Pass me the two-inch drill. It's on the table next to the prow of _Argo II. _

Nico trudged over and found the table easily enough. He then looked at the desk for a few minutes, trying to figure out which tool was the drill. To be honest, they all looked the same and Nico was fond of all his fingers. Sighing, he snapped his fingers and got four skeletons to carry the entire table over to Leo.

Leo sighed and said, "How are you ever going to learn, young padawan?" He dropped down from wing and said, "Alright. These are the drill bits, and they have their diameter written on the top." He showed Nico the little numbers, who shook his head and asked, "What in the name of the gods is a padawan?"

Leo stared at him in disbelief before saying, "You really did grow up in the 30's, didn't you. Alright, then." He took Nico by the arm and dragged him to the deck of the _Argo II_. Nico's legs flailed as he tried to avoid stepping on the more dangerous automatons and tools. As it was, he smelt his shoes burning from stepping on something he really didn't want to think about.

Ignoring this, Leo kept on dragging Nico up the rigging of the _Argo II _and pulled Nico into his room. Leo popped up from a drawer and held up six DVD's. "I got the Stoll's to sneak me these in return for helping them get back at the Ares kids."

Nico took one and looked at it quizzically. "The Phantom Menace? What's this?"

"This, my friend, is Star Wars." Nico took a seat as Leo quickly set up the movie and sat down next to Nico, putting an arm around him. Nico squirmed but Leo didn't let go. "Did you ever see movies in the 30's?"

Nico shook his head. "I know what they are, but I think this is the first one I'm watching."

Leo's mouth gaped, and he laughed again. "Well, my young padawan, you are in for a treat."

Nico jumped as the lights dimmed and loud music started playing , and forgot about Leo's arm around his shoulder. He straightened up and watched in awe as he was immersed in the world of lasers, Jedi, droids, and a little boy called Anakin Skywalker.

* * *

Several hours later, Nico was about to watch the Return of the Jedi. Leo had taught him how to change disks and since Leo had fallen asleep halfway through the fifth one, The Empire Strikes Back, Nico had taken it upon himself to install the final movie. He was amazed he hadn't blown up the TV trying to do so.

As Nico had stood up, he was suddenly aware of how cold he was without Leo leaning next to him. Bodies gave off a lot of warmth. Shaking his head, he plopped back down on the couch as the Star Wars theme song boomed in the surround sound system Leo had set up in his cabin.

As the movie started, Nico relaxed and thought about his conversation with Leo a few days ago about his mother. He hadn't talked to anyone about it, not even Percy who knew about it. Percy.

Nico wanted to hate him, but couldn't. Nico would feel angry whenever he saw Percy, but it was directed at himself. It was directed at his inability to be there for Percy, to be noticed by Percy. It was directed at his cowardice at never telling Percy why he had helped him in the Underworld years ago when Kronos was advancing on Manhattan.

Leo had felt the same kind of irrational hate. Nico saw it when Leo let his guard down. Whenever Leo was working on his great quest, whatever it was, he would drop the mask of jokes and puns. Nico felt privileged, like he knew Leo better than Jason or Piper.

He snorted bitterly. Like he could know more about Leo in the week and a half than Jason and Piper, who had been his best friends. It was just like him to delude himself about Leo, just like he had deluded himself about Percy.

Nico froze and shook his head. Leo was _not _like Percy. Percy was tall, handsome and reliable and kind and accepting and completely out of reach. Leo was fun, faithful, technologically brilliant, genuine, friendly, and completely out of reach.

Nico took a deep breath and deliberately concentrated on bounty hunters getting mauled by sand monsters. Leo _wasn't _like Percy. Hell, Leo conjured fire while Percy controlled water. You couldn't get much more opposite than that.

Nico sighed as Leo stirred and rested his head on Nico's shoulder. Nico realized that Leo smelt of oil and charred hair, just like Bunker 9. Or maybe Bunker 9 just smelt like Leo. Just then, Leo yawned and woke up. "Where are we at now?"

"Luke's back on Dagobah talking to Yoda." Nico's mouth was hanging ajar as he drank in the emotional death.

"Aw man, I can't believe I missed it." Leo moaned, "Were you amazed when Vader and Luke fought in the last movie?"

Nico shrugged. "It was okay, I guess."

"Okay, he guesses." Leo groaned and flopped around on the couch in mock outrage. "I show my padawan the most amazing plot twist in all of film history, and he says 'okay'. Do you now understand how many people in shock when it was first shown?"

"How would you know?" Nico asked, "It's not like you were there."

Leo exhaled, blowing back scraggly hair from his eyes. He really hated it when Nico said something logical like that. He'd been discovering a lot of things about Nico, like the death of his mom. Leo got a mental image of a mini-Nico glaring up at his mom like he was doing now. He had never imagined Nico with a mom, which he now realized was stupid. But this was the Ghost King, one of the most dangerous and unstable demigods in the entire camp, who would rather die than be in the middle of people. That image and motherly love just didn't go together.

But who was Leo to talk about outward appearances? Sometimes he acted like life was a joke, and he did it so well he sometimes convinced himself. But Nico had talked to him, and he had talked back. Face to face, with their defences down, the door open, so to speak.

Speaking of which, "Hey, Nico, when are you going to fix that door? It's been more than a week now."

"I'll get to it." Nico said, "Besides, it's not like anyone else comes in."

Leo laughed, a genuine laugh, and then they entered another silence. But this was an accepting silence, a comfortable silence. Neither of them minded it, and they watched the rest of the movie without talking.

After it ended, the two of them watched the credits roll for a few minutes, then Leo said, "It's getting pretty late." Nico raised an eyebrow and Leo laughed, "Okay, it is pretty late. Do you know what the time is?"

Nico shook his head. "I don't have a watch. Don't you have one outside?" Nico felt Leo's elbow poke him as he rummaged around in his toolbelt. He pulled out a glow-in-the-dark watch and said, "Wow, it's past midnight."

Nico smiled and said, "Time passed by quickly today. Watching movies is fun." Leo looked across at him as he put the watch back in his toolbelt and said, "I'm actually pretty hungry. We didn't eat anything when we were watching the movies."

"You can get up if you want," Nico said, "But I'm really too tired to move." As if to prove his point, Nico closed his eyes and rolled over. Leo looked at him for a moment, then shut his eyes as well. The two of them slept for a long time, and awoke several hours later the next afternoon.

* * *

"You know, Nico, I have discovered many things over the past few weeks."

Nico was helping Leo hammer in some metal plating into the hull of the _Argo II_ and looked up as Leo started talking.

"First of all, you are terrible at paying debts." Nico looked up in bewilderment at Leo, who was clambering over the railing of the _Argo II_ and coming down to where Nico was hanging with a few nails in his mouth.

"What do you mean?"

As an answer, Leo pointed at the open doorframe. "It's almost been a month. When are you going to fix it? I'm pretty sure you could do a good job now."

Nico shrugged. "You're talking to a demigod with ADHD. You really expect me to remember things now? It's not as if people usually want to come in."

Leo rolled his eyes as he inspected Nico's handiwork. He had been reluctant at first to trust Nico with tasks after his first few disasters with his tools. But Leo had been surprised when Nico had caught on quickly. Leo had even caught Nico fiddling with some tools on a small project of his own. Leo had no idea what it was, but Nico seemed happy fiddling with the small tools, and that made Leo happy.

"Second of all, you are a nerd."

"I am not a nerd."

"You love Star Wars,"

"Along with several million other people,"

"You spend hours playing games in my room,"

"If you grew up in the 30's the PS3 would seem godly to you. Besides, tell me you haven't spent hours trying to beat Dark Souls."

"And now I discover that you were into _Mythomagic._"

Nico's head jerked up as he saw Leo leaning over the deck and holding the statute of Hades that Percy had returned to him years ago. "Where did you get that?"

"I found it in your cabin when we were moving your stuff over here." Nico had forgotten he had kept the statute in his room. It wasn't surprising Leo had picked it up, the boy had an eye for random details no other ADHD demigod had. Leo had offered Nico to stay in his _Argo II_ cabin instead of always shadow travelling into the bunker and running the risk of crashing into various inventions. Nico's eyes had widened before nodding, and the two of them had gone to clear out his cabin.

Nico had insisted on doing it at night, and since their sleep schedules had still been out of sync because of the Star Wars marathon, Leo hadn't complained.

"Yeah, I played them after Alecto took me out of the Lotus Hotel but before I met Percy." Nico didn't mind saying Percy's name now, he didn't get that irrational anger whenever he thought of the demigod. He smiled absently and wondered what had changed.

"You played it a lot?" Leo climbed down the _Argo II _to look at Nico's handiwork. "Hey, you've done a pretty good job there."

Nico smiled again at Leo before saying, "Yeah, I did. Bianca never liked it that much though." Leo noticed Nico's face darken whenever Bianca's name was mentioned. "Percy gave it to me some years ago. It was after he asked me to stay at the camp."

"But you didn't." Leo said as he looked intently at Nico. The son of Hades shook his head and said, "I wouldn't be accepted. Hell, I'm still not accepted and that's after helping during the Second Titan War and the war against Gaea. Besides, I didn't think I deserved it."

"What do you mean?" Leo asked, "Everyone deserves love." He had started tapping out Morse subconsciously on the deck of the _Argo II_, a rhythm Nico always found soothing.

"I know it's stupid, but, well, I thought that if I had been there, Bianca wouldn't have died. It's like, well," Nico didn't know where to look. His fist clenched as he remembered Bianca's face, both in life and death. "Bianca was the only one that loved me. Hades never did, Persephone never did, Percy never-" Nico drew back a sharp breath and seemed to retreat into the shadows that sprung up around him like a caressing hand that was about to drag Nico back into darkness.

"What are you saying?" Leo asked, "What's-" Then he realized why Nico had acted so strangely around Percy. He realized why Nico's eyes had flashed dangerously whenever Leo had mentioned Percy. Looking back was like joining dots to make a picture, and everything made sense.

"Do you still…" It had taken Leo a few seconds to realize what Nico was saying, and now he didn't quite know what to say. "Do you still, you know, _like _like him?"

Nico shook his head. "As I said, it was stupid. I don't feel anything for him now."

Nico had said this time himself over and over again. He had said it as he lay in bed and thought about Percy. He had said it to himself almost all the time trying to convince himself otherwise. It never worked. Nico found himself being short of breath whenever he saw Percy and his fists would clench whenever he saw Annabeth. It had been his mantra, his motto, his one hope that one day he would be free from Eros' damned curse. That he wouldn't feel wrong or unnatural whenever he looked at Percy.

This time, Nico was shocked to find that he meant it. He had told himself over and over again how Percy wasn't his, and how what he was feeling wasn't really a crush, it was just friendship. But this time when he said it to Leo he realized what he was feeling was genuine. Percy didn't hold the same power over him anymore. And this realization brought him a sense of freedom and relief he had never felt before. What had changed in him? Why were his feelings for Percy finally changing?

Then he looked in front of him towards Leo, who was hanging onto a loose spar with one hand while looking with concern at Nico. Leo, who Nico was sure knew more about him than anyone except for Bianca. Leo, who had shown him Star Wars, movies, games, and so many other things that Nico suddenly loved doing. He remembered Leo's warmth; not the bright fires he was famous for in camp but his humorous yet compassion glow that was warmer than Hestia's hearth had been.

Nico realized what had changed.

* * *

"Okay, just finish regulating the sonar and we're done!"

Nico did as Leo told, grabbing the correct tools without needing to look and proudly accomplished the final task to outfitting the _Argo II_. After a month playing games, watching movies, playing _Mythomagic_, and helping Leo outfitting the _Argo II_ for whatever journey Leo was going on, Nico was as proficient with tools as any average child of Hephaestus. Of course, Leo could still run rings around him, but Leo was definitely not your average child of Hephaestus. Nico stepped back to admire his handiwork and sighed proudly. Nico took out a few tools from his pocket and started fiddling around again. It was his first project he was doing by himself, but it was going well. It would be done soon.

"You look like a proper Hephaestus kid." Leo said, strolling up next to him. "You've been fiddling around with something for a while." Nico shrugged then gestured up at the _Argo II. _Leo beamed happily, happier than Nico had ever seen him. "I gotta say, Nico, you have really gotten good with tools. I should take you over to the Hephaestus cabin and let you loose on the forge. You've done well, my padawan."

Nico chuckled and slung his arm around Leo. It seemed strange, but at the same time it seemed right. Nico felt more comfortable around Leo than he ever had around Percy. Maybe because all he had done was to look at Percy from afar. He could have never been comfortable around someone he idolized like that.

"You know, I never would've thought that you could have laughed so much when we first met." Leo said. "You were all gloomy and insane from your stretch in Tartarus."

Nico fiddled with one of the pockets on Leo's shirt, he had many, as he said, "I didn't know you. And you didn't know me." He then smirked and said, "Besides, I didn't know about these awesome things called movies and video games. They helped a lot."

Leo laughed and asked, "You're still on Dark Souls II, aren't you. After spending how many hours on _my _PS3?"

Nico rolled his eyes and said, "Dark Souls II isn't the only game I play. Besides, it's not like you ever kick me out of your room." Nico felt himself relax as he leaned on Leo slightly.

"After all that playing I'm just surprised your hands haven't been deformed." Leo smirked, "I've had to pry your hands away from the controller so many times." He reached inside his toolbelt and pulled out a pencil that he started twirling in his fingers.

"Your couch is comfy." Nico said shortly. Leo knew by now that whenever Nico said something short, there was always subtext behind the words. "The couch isn't the only reason you like playing games in my room, is it?"

Nico pulled away and looked at Leo intensely. They didn't say anything for a minute as a quizzical look from Leo met an intense gaze from Nico. The silence was broken by the son of Hades, who asked, "So now your ship's restored, do you want to tell me what you've been trying to do?"

"Alright, then." Leo said enthusiastically. "Have you heard of Calypso?"

Nico nodded slowly. "I heard the story from Percy. She's this girl on an island who falls for people that leave."

Leo nodded. "Well, the truth is, I fell on that island when we were on the _Argo II_ and separated."

Nico froze, not wanting to know where this was going. It couldn't be. How could this be happening? Leo's mouth kept on moving, but Nico's ears were turned inwards, and they could only hear Nico's thoughts and memories. Why him, why him, why him?

Leo had finished talking, and Nico nodded. "That sounds great. You're going to get her now?"

Leo nodded eagerly. "Of course, it's not going to be easy. I'll need more people with me, and of course a Jedi Master needs his trusty padawan, doesn't he?"

Words that had made Nico smile in pleasure now melted his lungs into a red paste until it felt like he was suffocating from within. "Sorry, I've got urgent business in the Underworld."

Leo frowned in confusion. "Business that just came up now? Can you put it off? I don't want to ask anyone else. Percy and Annabeth are visiting Camp Jupiter, and Jason and Piper have their hands full with stuff at the camp. Besides, you're the only one I trust."

Nico nodded slowly. "Yeah. Just give me a couple of minutes."

"Sure," Leo said, "We'll leave whenever you're ready, okay?" Nico nodded and shadow travelled out of the bunker before Leo could say anything. He didn't know where he ended up. It was nighttime here where it had been afternoon in Long Island, so he knew it was far away. His breath was still ragged, and tears streamed out of his eyes.

_Let me show you, my padawan._

Of course, his _padawan_, his apprentice. That was all Leo saw in him. He never loved Nico. No one ever would. How could Nico delude himself just because they had watched a few movies and played games together? All this time Nico had thought they were getting closer when in fact Leo was running away from him towards Calypso. It wasn't fair. It just couldn't happen.

Nico curled up in a ball on the ground and was aware of the earth around him decay into ashes and the tree trunks around him rotting slowly. He screamed as loud as he can, determined to destroy his throat in an unearthly howl. His voice broke and he just lay there silently in a huddle.

_Everyone deserves love._

Everyone except him, apparently. Leo loved someone else. At that moment, Nico wanted to kill Calypso. He wanted to rip her body to shreds and throw them in the ocean. But it would devastate Leo, and despite everything Leo had done for him, Nico would never hurt Leo. He couldn't. He wouldn't. Leo would never be his. No one would ever be his. It didn't matter if he was wrong or not for crushing on boys, no one would ever want him. He was the Ghost King. The formidable son of Hades. He would never be accepted and he would never be loved.

_Everyone deserves love._

Especially Leo. No one knew how good of a person Leo was except for Nico. And hopefully Calypso. If anyone deserved to be loved it was Leo, ingenious and loyal Leo, who smelt of oil, metal and smoke. Nico would help Leo, what else could he do? He would help Leo, like he had helped Percy, and then Nico would disappear from his life, just like he had disappeared from Percy's. Because that was all that Nico was capable of doing. Disappearing. Seeming like he wasn't there because he didn't deserve to be.

Nico dried his tears and stood up. He felt a cold detachment in his heart, as if there were cogs and gears that kept it running, and they were suddenly missing a piece. He went back to bunker 9, where he nodded to Leo and the two of them started flying.

* * *

The trip was uneventful, especially compared to their last one. There were only monster attacks two or three times a week. Still, Leo was on guard. Not because of the monsters but because of Nico. He stayed in his room the entire time he wasn't piloting the _Argo II. _He didn't say anything to Leo and brushed off any stabs Leo made at conversation.

It hurt Leo a lot, even more than the time he had left Calypso for the last time. When he had left, he knew he would return. When Nico had left and withdrawn into himself, Leo somehow felt that Nico wouldn't be coming back. And the thought that his padawan might be leaving him hurt a lot more than he would have thought when he had first met Nico.

Without Nico cursing at whatever had killed his character in the game for the thousandth time, his room seemed empty. So did the rest of the _Argo II_. Leo missed seeing Nico intently try to fix some gadget or help Leo with whatever he was doing. He normally liked it when he was alone with his inventions, but he wanted Nico now. Nico made everything seem funny and alive, which was ironic since he ruled the dead. Leo missed Nico talking to him about the latest movie they had watched, he had missed seeing this upbeat and nerdy side of Nico. Leo stroked Festus' head and whispered, "What happened?"

He didn't receive an answer.

He kept on fighting monsters and navigating, relying on Archimedes sphere to direct him to the region Ogygia had last been. But even when he fought alongside Nico, he still felt apart. They would fight like two people and usually they would just divide up the enemies from left to right. Leo realized how much he had smiled in Nico's presence, and how relaxed Nico had helped him feel. He desperately wanted that closeness now, but Nico didn't.

And he still didn't receive an answer.

But on the second week of their journey, he did receive an answer along with pain and sorrow that he hadn't realized he was capable of feeling.

He had cornered Nico one night on the deck of the _Argo II _and asked, "Okay, Nico, what's wrong?"

Nico didn't answer and tried to shove his way past Leo, but even though he was shorter, he could still shove Nico back and ask, "You're hurting me, Nico. Things just aren't the same with you around."

Nico's eyes blazed and Leo remembered why he had been scared of him before. "_You're _hurting _me_?" He barked out a bitter laugh and said, "You are the dumbest smart person I know."

Leo tried to grab onto Nico but Nico ducked and rammed the hilt of his sword into Leo's stomach. Leo doubled over and yelled, "I thought we were friends. Best friends. We understand each other like no one else has ever understood us. Why are you doing this?"

Nico's eyes darkened. If this had happened a month ago, Leo would have backed away, but he knew Nico wouldn't seriously hurt him, and knew that most of the time Nico was acting threatening to hide his own fear. Ploughing on, Leo said, "Please, I want what he had in the bunker. I want to watch movies with you and play games with you. I want to watch you throw your remote at the wall because you got killed again. I want to just _be _with you. I thought you did as well."

Nico took a deep breath and said in a dangerous voice, "It seems you don't understand me as well as you thought, Valdez. And I didn't understand you as well as I thought." Nico paused before saying in a voice so soft Leo almost missed it. "I thought we were more than friends."

And with that, Nico walked into his cabin, and Leo didn't follow him.

Forget the Slap Leo In The Face machine. Leo felt so bad he wanted a Stomp Leo Into The Ground So Hard He Appears In The Underworld machine. Except then he'd have to face Nico's _dad_, which was something Leo never wanted to do.

Leo ran his hand through his messy hair and leaned on Festus with tears streaming down his face. Why did he seem to mess everything up? He felt useless and stupid. He _was _useless and stupid. What kind of friend broke someone's heart like that? What kind of friend didn't notice their friend crushing on them?

Why did Leo mess everything up? He was a worthless friend. He didn't deserve someone like Calypso. He couldn't believe he'd done what Percy had to Nico.

Festus groaned in sympathy, and Leo let his head lie there for a while. He got up after a bit and went down to Nico's cabin. He didn't try to go in, but he knew Nico could hear him from outside. "Nico, I-I'm so sorry. I should've noticed. I should've told you, I should've done so many other things."

There was no response, but Leo kept on going. "I don't deserve your forgiveness, and after all I did, I don't deserve your friendship. I led you on and broke your heart again, and I don't deserve to feel happy again. I'm just so sorry."

There was still no response. "I just wanted to say, well, if you want to stay on this ship, then that's fine, but you don't have to. You can leave if you want, and I'll totally understand."

Leo laid his head on the door as a few more tears fell to the ground, then tried the door. It was unlocked. Nico was gone along with all the things he had put in there. The tools Leo had lent Nico were arranged neatly on the drawer along with the games Nico had borrowed from Leo's room. On the center of Nico's bed, he had left the project he had been working on. A torch that was fashioned like a lightsaber hilt.

Leo remembered the night the two of them had watched Star Wars together, and the time the two of them had fallen asleep in the same room. After that night they had fallen asleep so many other times watching more movies or playing games. No one else had played video games with Leo before, and it seemed like no one else would again. Leo wasn't even sure if he wanted to play video games now that he would think of Nico every time he touched a controller.

Leo held the lightsaber to his chest and lay down in Nico's bed, breathing in the familiar smell of faint decay. He fell asleep as he clutched the lightsaber hilt and buried his face in Nico's pillow.

The next day, Leo left the room as he had found it, then locked the room and hoped he would never return to it.

As he had sailed on without Nico, he felt brokenhearted. Before this, he had thought that it was just an overused metaphor, but now he knew that people really did feel like their heart was broken. It was as if it had trouble pumping blood into Leo's body and made him tremble in sorrow. His chest hurt all the time, and sometimes he wound end up gasping on the ground with more tears streaming out of his eyes.

Time didn't heal a broken heart, but Leo learnt to cope with it after a week, and when he met Calypso, he had patched it up with so much duct tape he had half-convinced himself that he was alright.

* * *

Leo's reunion with Calypso was sad and happy at the same time. It was sad because, well, every day on the _Argo II_ without Nico had been depressing. But when Calypso hugged him, Leo felt his heart lift for the first time in weeks. "I told you I'd come back."

Calypso drew back and bit her lip. "I'm glad you're okay."

Leo nodded enthusiastically and said, "You want to come aboard now?"

"I suppose so." Calypso looked around the island and said, "This place has been my home for thousands of years. It feels strange leaving it."

"I know." Leo said, "I can stay here a few days with you if you want to get used to the idea of leaving."

Calypso shook her head. "I would get most used to the idea of leaving if I actually left." She went back to her house and beckoned Leo to follow. "My garden is the only thing I'll truly miss." She sighed and started snipping off small sprigs of the beautiful plants and put them into pots. "We can grow more. That's the amazing thing about plants. Even if they die, just saving a small bit can help bring them back to life."

Leo thought of Nico's room and wondered if that was a small bit Leo had snapped off and preserved. The last remaining sliver of their friendship, or whatever their relationship had been to Nico. Could Leo bring that back to life?

He snapped out of it and started helping Calypso carry the pots back to the _Argo II. _He could tell already that the plants were turn out beautiful. Maybe some of Demeter's kids would like to help grow them. Leo would rather he stay away from wood, especially since he had the tendency to burn stuff.

The two of them spent a few hours transporting small pots over to the _Argo II_. After that, Calypso stood on the prow of the ship, next to Festus, as the _Argo II_ rose and left Ogygia. She turned and said, "You actually did it. Thank you. I never thought anyone could."

Leo smiled wanly and said, "No problem. I swore that I would, and here I am."

"The greatest heroes have washed upon my shores," Calypso said, "And none could do what you just did. Thank you." She stepped forward and kissed Leo full on the lips for several seconds. Just like last time, Leo's brain seemed to short circuit and there was a moment when all he saw was white and all coherent thought left him.

But as they broke apart, Leo couldn't help wonder what it would have been like if it had been Nico kissing him. What would it have been like if Leo had been the one to tilt his head up and open his mouth for Nico. Nico would have been hesitant and shy, but Leo wouldn't have minded. He would have embraced Nico, have egged him on. He would have wanted to feel Nico's hands on his back and up his shirt, toying with his brown skin underneath his tools. Leo would have encouraged him with his own hands, tapping his own rhythm all over Nico. And Nico would respond, liberating Leo from sorrow and guilt and filling him up with something purer and stronger.

Shuddering in a mixture of guilt and pain, Leo banished the thought from his head and locked it away, just like he had locked Nico's room away, and turned to show Calypso around the _Argo II._

* * *

When Leo and Calypso got back to Bunker 9, Leo realized that something was different. He looked around and realized with another pang what it was. The door to the bunker was closed.

He vaulted over therailing of the _Argo II _and ran over to the door. It must have been Nico who had closed the door. Nico had used what Leo had taught him and closed the door. Leo leaned his head on it for a moment before pulling away and going back to Calypso.

He told her he had to go check up on something before running out of the bunker and into camp. He was shocked at how much it had changed. His brothers had really done their job well. It had been almost three months since Leo had set foot in the main area, and it had changed a lot. Just like Leo.

"Leo! Where in the gods' name have you been?"

Leo turned around to see Piper running up to him and hugging him. "We saw the _Argo II _leave and thought you weren't coming back. Where were you?"

Leo smiled and said, "Hey, I wouldn't do that to you. Listen, have you seen Nico around?"

Piper cocked her head and said, "No, he hasn't been around here for a couple of months. Percy and Chiron are really worried about him."

Leo remembered that Nico had pretty much moved into bunker 9 two months ago. He guessed that everyone had thought Nico had left for somewhere. "So you didn't see him yesterday or anything?"

"Why would we have seen him yesterday?" Piper asked, "Do you know what's going on?"

Leo shook his head sadly. "I thought I did. Come over to Bunker 9 if you want me to tell you where I went. Jason can come too."

Piper nodded and said, "Jason's teaching campers about swordfighting. But he'll love to see you again. How about in a couple of hours?"

Leo nodded distractedly and ran over to the Hades cabin. He opened the door but nothing and no one was in there. Sighing, he trudged back to Bunker 9, where, for the first time in months, he had to open the door. It swung smoothly on its hinges.

His padawan had learned well, alright.

He went inside the bunker and closed the door.

* * *

**I'm actually pretty sad now…**

**When I started this fic, I always meant for Leo to end up with Calypso. But as I finished writing it I was tempted for a moment to change the ending. I really feel sorry for Nico. I hope you guys felt sad too.**

**Please review if you enjoyed it. It would really make me happy.**

**Thanks!**


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